Improvement in dental molds



UNITED STATES PATENT OEEIcE.

ABRAM T. -KEIGHTLEY, OF GREENGASTLE, INDIANA.

.IMPROVEMENT IN DENTALl MOLDS.

Specification forming part of Letters Patent No. 173,641?, datedFebruary 1.5, 1876; application filed December 31, 1875.

To all whom it may concern.-

Beit known that I, ABRAM T. KEIGHTLEY, of Greencastle, in the 'county ofPutnam and State of Indiana, have invented a new and valuableImprovement in Stamping Teeth on Celluloid Plates; and I do herebydeclare that the following is a full, clear, and exact description ofthe construction and operation of the 4same, reference being had to theannexed drawings, making a part of this specification, and to theletters and figures of reference 'marked thereon. A Figure l of thedrawings isa representation of a side view of my stirrnp, With-the moldvertically sectioned 5 and Fig. 2 is a plan view of the mold.

This invention has relation to a preparatory 'process for securing teethon celluloid plate,

used by dentists in the manufactureof sets ofteeth for practical use.

The nature of the invention consists in so securing the plaster ,of theupper mold, when placed in the Hask, by a metal ring that expansion ofthe mold while under pressure is effectually prevented, as willbemhereinafter .is taken, this cast is covered with a thin plate of wax,which is made to conform properly to the surface. Uponthis the selectedteeth are placed in order, banked up with wax, to imitate, as nearly aspossible, the fullness of the natural gum around the teeth. -When thisis completed, and while yet on the mold, a reverse cast is taken ofteeth, wax, and all.

' The first mold, underneath is now. removed,

leaving wax, plate, and teeth attached to the second or uppermost mold.The wax is now melted away, leaving the-teeth clean, and embedded inthis last mold in the required position for the next process, with therivet ends,

or roots,7 projecting above the molded surface. At this point the firstcast is placed in the liask and secured. A blank of celluloid is thenlaid over it, the second mold containing the teeth is placed exactlyupon this, the flask' put in position, and all placed in the stirrup andin the heater. As the heat softens the celluloid blank, the upper moldis slowly and constantly brought down by a screw in the stirrup actingon the follower Vof the flask. This gradual pressure stamps or embedsthe teeth in the celluloid so firmly that no ordinary usage can dislodgethem. 1f thepressure is ,applied too rapidly or exceeds afcern tainlimit, the .upper mold expands, so as to break or utterly ruin theteeth. It is this frequently-recurring mischief which my invention isdesigned to prevent, and it is effected in the following manner:

Referring to the letters and figures of reference, A, Fig. l, representsthe lower and B the upper molds, between which the celluloid and teethare pressed. When the Wax andl teeth are placed in position on the lowermold,

they are secured in the iask by filling in with plaster, in the usualWay. The metal ring or band a, preferably made of tin or zinc, the endsof which are usually `joined by a lapseam, is placed on, surrounding theteeth at a quarter of an inch, more or less, distant from them, andresting on the prepared surface of the mold at b, and nearly even withthe lip of the lower flask c, as shown in Fig. 1. The

band, which is left embedded in the upper mold, becomes aprotection toit, and prevents any expansion or lateral displacement, that oftenoccurs by virtue of the wedge-like formation of the entire tooth-arch,as it gradually sinks by pressure into the celluloid, which 4itself mustconform to the outwardly-inclined angle of the lower mold, as shown atf. This stantialljr in the manner and for the purpose ring,T or band isapplicable to the protection of specified.

"molds for lower as well as upper sets of teeth. In testimony that Iclaim the above I have What I claim as new, and desire to securehereunto subscribed my name in the presence by Letters Patent, isof twoWitnesses.

A metal band or ring embedded iu the plasi ABRAM TIMOTHY KEIGHTLEY. teraround the teeth, to prevent expansion of Witnesses: the same whenpressure is applied in stamp- WM. HILL,

ing or setting the teeth in Celluloid plate, sub- L. E. BOSWELL.

